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The time-dependent exchange-correlation potential has an unusual task in directing fictitious non-interacting electrons to move with exactly the same probability density as true interacting electrons. This has intriguing implications for…

Chemical Physics · Physics 2024-06-19 Davood Dar , Lionel Lacombe , Neepa T. Maitra

We formulate a rigorous method for calculating a nonadiabatic (frequency-dependent) exchange-correlation (XC) kernel required for correct description of both equilibrium and nonequilibrium properties of strongly correlated systems within…

Strongly Correlated Electrons · Physics 2014-10-13 Volodymyr Turkowski , Talat S. Rahman

We consider electronic exchange and correlation effects in density-functional calculations of two-dimensional systems. Starting from wave function calculations of total energies and electron densities of inhomogeneous model systems, we…

Mesoscale and Nanoscale Physics · Physics 2012-05-30 Ilja Makkonen , Mikko M. Ervasti , Ville Kauppila , Ari Harju

We investigate an extension of excited state mean-field theory in which the energy expression is augmented with density functional components in an effort to include the effects of weak electron correlations. The approach remains…

Chemical Physics · Physics 2020-02-05 Luning Zhao , Eric Neuscamman

The asymmetric Hubbard dimer is used to study the density-dependence of the exact frequency-dependent kernel of linear-response time-dependent density functional theory. The exact form of the kernel is given, and the limitations of the…

Strongly Correlated Electrons · Physics 2018-07-17 D. J. Carrascal , J. Ferrer , N. Maitra , K. Burke

In time-dependent density-functional theory, a family of exchange-correlation kernels, known as long-range-corrected (LRC) kernels, have shown promise in the calculation of excitonic effects in solids. We perform a systematic assessment of…

Materials Science · Physics 2017-05-31 Young-Moo Byun , Carsten A. Ullrich

A new parameter-free approximation for the exchange-correlation kernel $f_{\rm xc}$ of time-dependent density functional theory is proposed. This kernel is expressed as an algorithm in which the exact Dyson equation for the response as well…

Materials Science · Physics 2015-05-28 S. Sharma , J. K. Dewhurst , A. Sanna , E. K. U. Gross

We investigate a number of formal properties of the adiabatic strictly-correlated electrons (SCE) functional, relevant for time-dependent potentials and for kernels in linear response time-dependent density functional theory. Among the…

Strongly Correlated Electrons · Physics 2016-08-24 Giovanna Lani , Simone di Marino , Augusto Gerolin , Robert van Leeuwen , Paola Gori-Giorgi

In order to assess the accuracy of commonly used approximate exchange-correlation density functionals, we present a comparison of accurate exchange and correlation potentials, exchange energy densities and energy components with the…

Condensed Matter · Physics 2007-05-23 Claudia Filippi , Xavier Gonze , C. J. Umrigar

We show that as an electron transfers between closed-shell molecular fragments at large separation, the exact correlation potential of time-dependent density functional theory gradually develops a step and peak structure in the bonding…

Chemical Physics · Physics 2014-02-11 Johanna I. Fuks , Peter Elliott , Angel Rubio , Neepa T. Maitra

Density functionals with a range-separated treatment of the exchange energy are known to improve upon their semilocal forerunners and fixed-fraction hybrids. The conversion of a given semilocal functional into its short-range analog is not…

Chemical Physics · Physics 2019-09-09 Dimitri N. Laikov

Local density approximation for the exchange energy is made for treatment of excited-states in density-functional theory. It is shown that taking care of the state-dependence of the LDA exchange energy functional leads to accurate…

Other Condensed Matter · Physics 2007-05-23 Manoj K. Harbola , Prasanjit Samal

We derive an exact representation of the exchange-correlation energy within density functional theory (DFT) which spawns a class of approximations leading to correct long-range asymptotic behavior. In what amounts to be the simplest…

Materials Science · Physics 2009-11-10 Roi Baer , Daniel Neuhauser

The adiabatic connection fluctuation-dissipation theorem with the random phase approximation (RPA) has recently been applied with success to obtain correlation energies of a variety of chemical and solid state systems. The main merit of…

Materials Science · Physics 2015-03-20 Thomas Olsen , Kristian S. Thygesen

Time-dependent density functional theory continues to draw a large number of users in a wide range of fields exploring myriad applications involving electronic spectra and dynamics. Although in principle exact, the predictivity of the…

Chemical Physics · Physics 2023-08-14 Lionel Lacombe , Neepa T. Maitra

Electron correlation in solid has a major impact on material properties. However, it has been studied mainly by theory, with very limited direct experimental investigations. Here, we report the results of real-space measurement of dynamic…

The derivative discontinuity of the exchange-correlation functional of density-functional theory is cast as the difference of two types of electron affinities. We show that standard Kohn-Sham calculations can be used to calculate both…

Chemical Physics · Physics 2007-12-13 F. P. Rosselli , A. B. F. da Silva , K. Capelle

We derive a generalized gradient approximation to the exchange energy to be used in density functional theory calculations of two-dimensional systems. This class of approximations has a long and successful history, but it has not yet been…

Strongly Correlated Electrons · Physics 2009-01-07 S. Pittalis , E. Rasanen , J. G. Vilhena , M. A. L. Marques

Reporting extensions of a recently developed approach to density functional theory with correct long-range be-havior (Phys. Rev. Lett. 94, 043002 (2005)). The central quantities are a splitting functional gamma[n] and a complementary…

Materials Science · Physics 2017-09-13 Ester Livshits , Roi Baer

We consider density functionals for exchange and correlation energies in two-dimensional systems. The functionals are constructed by making use of exact constraints for the angular averages of the corresponding exchange and correlation…

Strongly Correlated Electrons · Physics 2010-02-25 E. Rasanen , S. Pittalis